[chromedriver] Implement command: executeAsyncScript and setScriptTimeout

chrome/test/chromedriver/js/execute_async_script.js

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+* Execute the given script and save its result.

[kkania, 2013/03/08 17:25:12]

saves its asynchronous result

[chrisgao (Use stgao instead), 2013/03/08 21:06:24]

Done.

+*
+* A callback function {function(*) : null} will be appended to the end of
+* <code>args</code>.
+* The script should call this callback when it is completed. The value passed to
+* this callback will be saved in window.chromedriverAsyncScriptResult. Variable

[kkania, 2013/03/08 17:25:12]

try not to include unnecessary implementation details in the comment for the
function, which should just describe the interface and any prerequisites.  You
can move such a comment into the body of the function, but actually I'd be fine
with just dropping this part.

[chrisgao (Use stgao instead), 2013/03/08 21:06:24]

Done.

+* window.chromedriverAsyncScriptFinsished indicates whether the script
+* is completed.
+*
+* If script1 is executed before script2, but script1 completes after script2,
+* then script1's result will be discarded while script2's will be saved.
+*
+* @param {!string} script The asynchronous script to be executed.
+* @param {Array.<*>} args Arguments to be passed to the script.
+*/
+function executeAsyncScript(script, args) {
+  var idName = 'chromedriverAsyncScriptId';

[kkania, 2013/03/08 17:25:12]

how about:

function getAsyncScriptInfo() {
  var key = 'chromedriverAsyncScriptInfo';
  if (!(key in document))
    document[key] = {id: 0, finished:false};
  return document[key];
}

then you can call this here and in your tests

[chrisgao (Use stgao instead), 2013/03/08 21:06:24]

Done.

+  var finishFlagName = 'chromedriverAsyncScriptFinsished';

[kkania, 2013/03/08 17:25:12]

i think technically you don't need the finish flag since we autoconvert
undefined to null, but let's keep it in case we change that down the road.

[chrisgao (Use stgao instead), 2013/03/08 21:06:24]

ok.

+  var resultName = 'chromedriverAsyncScriptResult';
+  if (!(idName in document))
+    document[idName] = 0;
+  document[idName] ++;

[kkania, 2013/03/08 17:25:12]

style says no space i thnik

[chrisgao (Use stgao instead), 2013/03/08 21:06:24]

Done.

+  document[resultName] = null;

[kkania, 2013/03/08 17:25:12]

what's the point of this?

[chrisgao (Use stgao instead), 2013/03/08 21:06:24]

If last script timeout, its result might still be saved.
So delete the result ref instead of setting it as null.

+  document[finishFlagName] = false;
+  var id = document[idName];
+
+  function callback(result) {
+    if (id == document[idName]) {

[kkania, 2013/03/08 17:25:12]

i can think of two improvements here:
1) if the user specified a timeout of 0, which is default, we should only return
a result if the callback is called synchronously.
2) we should automatically remove the reference to the result when it is no
longer needed

[chrisgao (Use stgao instead), 2013/03/08 21:06:24]

1) Raise Timeout error below if this case happens.
2) Remove ref to result in the script within window_commands.cc for pulling
result.

+      document[resultName] = result;
+      document[finishFlagName] = true;
+    }
+  }
+  args.push(callback);
+
+  new window['Function'](script).apply(null, args);

[kkania, 2013/03/08 17:25:12]

I don't think you need  the window.  new Function(script) should be fine...

[chrisgao (Use stgao instead), 2013/03/08 21:06:24]

Done.
Also set error code here.

+}